In transportation and land use planning, access or accessibility is the ability for people to reach goods, services, and activities.

Another way to define access is people’s ability to meet opportunities, where opportunities are groceries, employment, education, healthcare, and other things they need and value.

A key component of access is mobility, the ability to move through physical space. Mobility is a means to access, but generally not a useful end itself. 

The words “access” and “accessibility” have other uses that are related but different. For example, in the context of people with disabilities, accessibility can refer to equity in mobility. 

Accessibility is also an important part of equity on general. Access in equity can refer to ensuring communities who have suffered and continue to suffer from historical injustices and exclusions now have what they need for well-being, including physical safety, nutrition, health, education, finance, and economic opportunities.

Access is fundamental to climate-resilient development and GHG mitigation.

Measurement

One of the contributions of the concept of access is that it provides a way to quantify the extent to which people can get what they need, and by extension, community health, well-being, and other public outcomes policymakers wish to pursue.

One way to provide access is reachability, or the capacity to physically reach opportunities. Reachability is comprised of the following:

#1. PROXIMITY: Physical distance between origins and destinations. The mix and breath of locations of key opportunities relative to people who need them. Proximity can be measured as the average time to reach one or a basket of key locations by a targeted or wider number of the population.

#2. MOBILITY: Ease or comfort of physical movement along a network. Metrics for mobility are well-established and include average travel speed and auto travel time abstracted from the impact of decisions on other travel modes. Here is a short talk by Jonathan Levine on conventional mobility measures and why they work when properly applied, but also lead us in wrong direction if we try to maximize for them without an organizing goal of accessibility.

#3 FREEDOM FROM BARRIERS: Removal of  impediments to using transport options. This includes affordability, safety, comfort, and other qualities that arise in different settings and with people’s needs. 

Another solution to access is connectivity, which means things coming to you. Connectivity could be for physical goods like water and delivery packages. It could also be digital resources like computing and communications which can (but doesn’t necessarily) provide cost-effective substitutes for physical travel. Connectivity could also be for fire and other emergency services.

In sum, access gives a way to measure meaningful outcomes and internal dynamics in a way that generally is currently lacking in transportation, land use, and related planning.

Practical Use

The idea of access as an integrated transportation and land use strategy brings some advantages. However it is not yet widely used by local governments, a fact that is explained partly by decades of auto-centric decisions in multiple levels of government that has created inertia.

Yet, access as a concept is available for local governments to use—and indeed, offers a way to leadership and innovation that could be valuable.

Some things the concept of access could do for a local government:

• Create a unified way to measure, manage, and optimize resources across multiple modes and investments towards human-centered outcomes
• Bring together various existing policy issues (e.g. commute times to work, availability of low-stress bikeways, wheelchair access, etc) into a single rubric.
• Establish a focal point to integrate planning activities that are currently diffused and disparate (e.g., parking policy and TDM proposals), creating the potential for a more powerful and deliberate way to coordinate investments 
• Provide a new way to evaluate equity with a higher degree of discernment and control in managing initiatives aimed to increase well-being in targeted populations.

In conclusion, access provides a way to understand and integrate the management of transportation and lanes use across modes and in urban, suburban, and rural environments.